1. Technical Field
This invention relates to refuse compactors and in particular to means for controlling the position of the compacting ram in a refuse compactor.
2. Background Art
In conventional refuse compactors, a ram is caused to move from a retracted position against refuse contained in a suitable receptacle so as to cause desired compaction of the refuse therein. The compactor apparatus includes means for effecting an automatic retraction of the ram to a retracted position when the compacting force reaches a preselected value.
It has been found that by maintaining the compacting force against the refuse rather than immediately causing retraction of the ram, an increased amount of compaction of the refuse can be effected. A number of devices have been developed for effecting such maintained compacting force operation in such compactor apparatuses.
Illustratively, in U.S. Pat. No. 3,229,618 of Leon P. O'Connor, Jr., a refuse disposal apparatus is shown wherein hydraulic pressure is maintained at a preselected maximum so as to maintain a packer plate in an extended limit position until a forward switch is released to effect a return of the packer plate to the retracted position. Such retention of the packer plate in the extended position is effected so as to facilitate securing of the retainer plate to the receiver when the receiver has been filled to a maximum capacity. Specifically, when the receiver has been filled to maximum capacity, the forward switch is actuated to move and hold the packer plate in a fully extended position. In this position, the latch mechanism is actuated to release the retainer plate and the retainer rods are employed to secure the retainer plate over the entrance opening in the receiver, permitting the receiver to be detached from the packer unit so as to be hauled to a final disposal area, as desired.
In U.S. Pat. No. 3,855,919, Richard W. Potter shows a control system for a compacting apparatus including signal lamps for showing the direction of movement of the ram. The apparatus includes a time delay circuit for automatically shutting down the compactor when any of the operational cycles thereof continues beyond a predetermined time limit.
In U.S. Pat. No. 3,398,433 of Charles J. Borum, a trash compactor with a clock timer control is disclosed for providing an extended delay period after a compacting stroke. The clock is provided to permit the automatic extended compaction at a period of time during the day when the compactor is unlikely to be in use for a substantial length of time. The control operates the ram independently of any manual initiation of the apparatus to effect the compacting stroke at the predetermined time and to cause the stopping of the ram for the delay period during that independently initiated compaction stroke.
Einar O. Engebretsen shows a compactor cycle control in U.S. Pat. No. 3,962,964 wherein a dwell period is provided at the end of the compaction cycle. In the Engebretsen control, a centrifugal switch closes just before the ram drive motor stops so as to complete a reverse starting circuit through the apparatus direction switch. A circuit breaker in the apparatus opens in response to the heavier starting current so as to open a bypass circuit around the start switch and cause the motor, which is in the process of reversing, to stop. Engebretsen teaches that the reversal movement is stopped almost instantaneously so that any retraction from the bottom-most point of travel would be little. Thus, the amount of actual retraction is a function of the rapidity with which the circuit breaker opens in response to the reversal starting current. In an alternative embodiment, Engebretsen teaches the use of a start relay which has its holding circuit opened at the point of maximum compaction, to thereby effect a pause cycle.